1. Field of the Invention
The present invention relates to imaging systems and methodologies. More specifically, the present invention relates to countermeasures for infrared sensing systems.
2. Description of the Related Art
Imaging systems are used for a variety of commercial, industrial and military applications. Of particular interest for military applications are infrared sensing systems and techniques. Infrared sensing systems detect heat and are therefore effective in conditions of darkness, smoke, haze and other situations where visible detection is impractical. Accordingly, many weapons have been developed which rely on infrared sensors for target acquisition and tracking and terminal guidance. The development of weapons with infrared technology has given rise to a need for countermeasures for same.
Several techniques are used in the art for infrared countermeasures or ‘IRCM’. Conventional IRCM countermeasures include sensor blinding, lethality-based approaches, and modulated lasers for “spoofing.” In most of these cases, a high-energy or high-power laser is required. In the “spoofing” approach, for example, a laser beam is temporally modulated to confuse the navigational homing system in the threat vehicle. The laser beam must be spread in angle to cover a field-of-view (FOV) of sufficient breadth to illuminate a target.
Unfortunately, the efficiency of the spoofing approach, as well as other IRCM approaches, is limited by atmospheric distortions and other aberrations that tend to impede the diffraction-limited performance of the system. As a result, most of the light “spills over” the target, and represents a loss to the system. In addition, residual beam wander, due to excess vibrations, finite servo gain on trackers, etc., creates the need to increase the angular spread of the IRCM modulated laser beam, to assure adequate target illumination. Consequently, this approach requires a high-power source which adds to the size, weight, cost and power requirements of the system and limits the performance thereof.
Hence, a need exists in the art for an improved system or method for focusing infrared energy on a moving target and maintaining it on the target throughout its flight path. A further need exists for a system for focusing infrared energy on moving target with temporal encoding or modulation to effect spoofing for countermeasure protection.